Line Striper

ABSTRACT

Herein is an apparatus for overlaying a media stripe onto a media stripe previously applied to a surface (i.e., “old media strip”). The apparatus includes a mobile frame housing controls and an applicator head having a spray nozzle that applies new media. The applicator head also includes sensors and/or a camera that cast a cone of vision onto a surface. The cone of vision is positioned tangentially to a first edge of the old media stripe. If while operating the apparatus, the applicator head moves and the new media stripe is not overlaid onto the old media stripe, the sensors and/or camera will direct an actuator arm (or similar) to reposition the applicator head and spray nozzle so that the new media stripe is once again sprayed on top of the old media stripe.

BACKGROUND OF THE INVENTION

The present invention relates generally to the application of media onto a surface from a device in motion, e.g., a line striper apparatus.

Stripes are applied to roadways, parking lots, warehouse floors and the like for directing the movement and placement of people, things, and vehicles. Every year thousands of miles of roads and countless square miles of parking lots, warehouse floors, airport floors and runways, and athletic fields are re-striped when the existing surface markings fade because of the natural erosion of time and the elements. Safety, traffic flow, and athletic events rely on clearly visible surface markings and boundaries. There is a need to continuously maintain these markings.

One challenge in re-striping the markings is the precision at which the new stripe overlays onto the existing stripe. While various types of video and mechanical guidance systems are known for use with vehicle mounted line stripers, all systems known to date suffer somewhat in that while attempting to re-stripe over an existing line, despite the advancement of the guidance systems, the re-striping still relies to a great extent on the operator. For example, as shown in U.S. Pat. No. 6,811,351, the driver of the cab must follow a guide rod positioned above the stripe on the road on a forward looking video system in order for the apparatus to re-stripe the line near the rear of the vehicle. If the driver is distracted and the guide moves off of the existing line, the new, re-striped line will not properly overlay the old line. Thus, as with any repetitive task, user operator error is the main source of error. The present invention is directed to minimizing user introduced error when re-striping surfaces.

SUMMARY OF THE INVENTION

Described herein is an apparatus for applying a new media stripe onto or overlaid onto a media stripe that has been previously applied to a surface (i.e., “old media stripe”). The apparatus has a mobile frame housing controls, an applicator head and an extendable arm that connects the applicator head to the mobile frame. The applicator head has at least one sensor and/or camera that casts a cone of vision position tangentially to the edge of the old media stripe. The applicator head also has a media nozzle adapted to spray media overlaid on the media stripe previously applied to a surface. The media nozzle is positioned at a distance from the at least one sensor and/or camera so that when the sensor/s and/or camera “see” the old media stripe, the at least one sensor and/or camera communicates with the controls to align the applicator head housing the media nozzle so that the new media stripe is applied on top of the old media stripe.

Also disclosed is a method of using the apparatus described herein which allows for simultaneous application of a new media stripe onto an old media stripe while correcting for and misalignment of the spray nozzle by the user.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is best understood from the following detailed description when read in connection with the accompanying drawing. It is emphasized that, according to common practice, the various features of the drawing are not to scale. On the contrary, the dimensions of the various features are arbitrarily expanded or reduced for clarity. Included in the drawing are the following figures:

FIG. 1 is an exemplary embodiment of an apparatus for applying media stripe onto a surface according to the invention;

FIG. 2 is a detailed, partial view of the applicator head of the apparatus shown in FIG. 1;

FIG. 3 shows the movement of the extendable arm repositioning the applicator head of the apparatus shown in FIG. 1;

FIG. 4 shows the relationship between the media discharge nozzle and the first and second sensors and/or camera of the applicator head shown in FIG. 2;

FIG. 5 shows the first and second sensor and/or camera cones of vision positioned at the edges of a previously applied media stripe; and

FIG. 6 shows an event where more than one media stripe that has been previously applied to a surface do not exactly overlap.

DETAILED DESCRIPTION OF THE INVENTION

The present invention simplifies the line striping process making it more accurate, efficient, and/or less labor intensive. According to an embodiment, the invention is an actuated sensing system that controls the position of a spray nozzle of a self-contained striping apparatus. The system comprises a user interface with controls that communicate with multiple sensors and/or a camera which determines the edges of an existing media line or stripe. According to one embodiment, the pressure and/or volume of the flow of media is fixed, however, according to alternative embodiments, the controls also adjust the pressure and/or volume of the flow of media from the discharge nozzle. The sensors and/or camera determine where the previous media stripe was applied to the surface. They communicate with the controls, which use this information to reposition the discharge nozzle, as necessary, in a way that “follows” the previous media stripe so that the newly applied media stripe overlays the old media stripe. Therefore, when the system is mounted to a walk-behind unit, a ride-behind unit, or a vehicle, the system allows quality striping at higher speeds.

With reference now to the figures where an embodiment of the invention is described, FIG. 1 shows a walk-behind line striper 1 having frame 10 mounted on a movable carriage 25. Mounted to carriage 25 are user interface 5, controls 15, and media reservoir 20. Although the invention is exemplified in the Figures as adapted to be mounted to a walk behind apparatus as in U.S. Pat. No. 7,673,815, other line striping apparatus are contemplated such as a vehicle as in U.S. Pat. No. 5,368,232 or towed behind a truck similar to U.S. Pat. No. 5,947,385, or self powered as in U.S. Pat. No. 5,947,637—all of which are incorporated by reference.

User interface 5 may comprise two toggle switches, a push button reset switch, and indicator lamps (not shown) that indicate an error in the line striping application process such as over travel, i.e., when the newly applied media is being misapplied over the old media stripe. Exemplary indicator lights are those manufactured by Mouser Electronics. Controls 15 may comprise a Programmable Logic Controller (PLC) such as those manufactured by Allen Bradley.

An actuator 45 is mounted to carriage 25 at actuator carriage end 35 and extends, as shown in this exemplary embodiment, as extending perpendicular to the direction of travel of line striper 1. Mounted to the other end of the actuator 45, also referred to herein as applicator head housing end 40, is applicator head housing 100. Applicator head housing 100 contains multiple components, including sensors and/or a camera (not shown) and media applicator 30. According to an alternative embodiment, depending on the type of media being applied and the application speed, a second set of sensors and/or a camera are mounted independent from the media applicator head. According to this alternative embodiment, a second actuator is mounted to the same carriage, or a separate carriage, to house the second set of sensors and/or a camera, which are independent from the applicator head housing. The second set of sensors and/or a camera are used to detect the old media stripe and the applicator head housing having its sensors and/or its camera positions the media discharge nozzle. These two sets of sensors and/or cameras on the same or different carriages are calibrated to adjust for the ground speed and travel heights of the line striper, respectively.

FIG. 2 shows applicator head 100 in more detail. In this particular embodiment of applicator head 100, an applicator head plate 120 is adapted to receive and maintain media discharge nozzle 110 in a position such that when media is discharged from the nozzle, the media are applied onto a surface. In the embodiment of the invention shown in FIG. 1, the media discharge nozzle is oriented so that the media is dispensed downward onto the surface as line striper 1 is moved. Adjustably mounted to head plate 120 via a first sensor and/or camera slot 130A is first sensor and/or camera 130. Similarly, also adjustably mounted to head plate 120 via a second sensor and/or camera slot 140A is second sensor and/or camera 140. Exemplary sensors include photo switch and inductive proximity switch sensors such as those manufactured by Allen Bradley. Two sensors are shown in the embodiment of FIG. 2, however, more than 2 sensors may be used. A camera system may also be used such as a camera manufactured by Cognex. At least two sensors and/or a camera are required to track along the outside edge of the existing line.

Also shown in FIG. 2 is old media stripe 310 to illustrate how the sensors and/or camera “see” an old line painted on a surface such as a road. For example, the first sensor and/or camera 130 is positioned so that it cone of vision 135 “sees” the surface immediately adjacent to an edge of the old media stripe 310 (designated with an X). The second sensor and/or camera 140 is likewise positioned so that its cone of vision 145 “sees” the surface immediately adjacent to the opposite edge of old media stripe 310 as shown in more detail in FIG. 4. According to this embodiment, the sensors and/or cameras 130 and 140 are connected to actuator arm 45 via applicator head 100, however, the sensors and/or cameras may be attached to any portion of line striper 1 so long as the sensor and/or camera cone of vision is immediately adjacent or tangential to the surface of the old media stripe.

In the embodiment of the camera system, one or more multiple cameras are connected or linked to a main image processing unit. The connection may be made to specialized intermediate hardware like a frame grabber using either a standardized or custom interface. Alternatively, the cameras or camera has image process capabilities built in, which are generally referred to as a smart cameras or smart sensors. After the image is acquired, it is processed through machine vision software using methods known to one of ordinary skill in the art. The outputs of the machine vision software instruct the movement of actuator 45 to position the applicator head housing 100 into a position so that a media stripe is applied to a surface or reapplied over an existing media stripe.

FIG. 3 shows the embodiment of the invention shown in FIG. 1 in motion. As line striper 1 is moved along, parallel, or next to old media stripe 310, the sensors and/or camera (not shown in FIG. 3, but described in detail with respect to FIG. 4) “see” the surface immediately adjacent to the edge of old media stripe 310 (i.e., the cone of vision is tangential to the edge of the previously applied media stripe). The operator positions line striper apparatus 1 such that applicator head housing is in a first position 100A over media stripe 310. If the operator of the line striper apparatus 1 misguides the apparatus or the old media line is curved and applicator head housing 100 and spray pattern of the newly applied media 300 is no longer aligned over old media stripe 310, the sensors and/or camera “see” the misalignment (represented by applicator head 100B) by sensing the difference from the old media stripe compared to the uncoated surface. The sensors and/or camera feed this information back to controls 15, which automatically instructs actuator 45 to reposition applicator head housing 100 into a corrected position (represented by applicator head 100A). The result is that the application of new media stripe 300 from line striper apparatus 100 is overlaid onto old media stripe 310. Accordingly, during normal operation, the cones of vision, 135 and 145, of both sensors and/or cameras 130 and 140 track along the outside edge of existing media stripe 310. In the event that either sensor and/or camera detects the old media stripe 310, said sensor and/or camera will send a signal to the PLC and the PLC will reposition actuator 45 in the appropriate direction. Actuator 45 will continue to move until said sensor and/or camera no longer detects old media stripe 310.

Moreover, according to an embodiment of the invention, when actuator 45 is near fully extended (or retracted), an over-travel sensor and/or camera (not shown) at user interface 5 will trip a warning light and a reset button (also not shown) must be pushed in order to realign applicator head housing end 40 and realign spray pattern of newly applied media 300 over old media stripe 310.

The sensors and/or camera and automatic features embodied in this invention allow for greater precision (i.e., correct any operator error caused by misalignment of the new media spray onto the old media spray) and allow the line striper apparatus to apply new media faster.

In an embodiment, actuator 45 is a worm screw, piston, cable, belt, hydraulic cylinder or any mechanical device that provides for movement of applicator head housing 100. The actuator movement shown in the embodiment of FIG. 3 is bidirectional (e.g., it moves in or out) and is perpendicular to the direction the line apparatus travels. However, also contemplated is an actuator that can reposition applicator head housing multidirectionally (both in and out, and forward and backward with respect to the travel direction of the line striper apparatus). Also contemplated is an actuator that can reposition applicator head houses closer to or away from the surface to which the media is applied. In this embodiment, the nozzle responsible for the spray width of the media can remain the same, while the spray width can be narrowed or widened depending on the distance the applicator head housing is moved from the surface to be sprayed.

Shown in FIG. 4 is an embodiment of the components of applicator head 100. First sensor and/or camera 130 and second sensor and/or camera 140 are arranged such that the sensor and/or camera cones of vision 135 and 145 “sees” the surface immediately adjacent to each edge of old media stripe 310. The center of the cone of vision are represented by reference numerals 137 and 147, respectively. The respective centers are equidistant from a point that is the center of media spray width 150. Thus, distance X from center of media spray width 150 to center of circle 137 cast by sensor and/or camera cone of vision 135 of first sensor and/or camera 130 is equal to distance Y from center of media spray width 150 to center of circle 147 cast by sensor and/or camera cone of vision 145 of second sensor and/or camera 140. Media discharge nozzle 110 is positioned at a height above the surface to which the media is being applied or the nozzle spray width is adjusted such that when media is sprayed, new media stripe 300 is formed having a width (shown as distance Z) equal not only to the distance between the first and second cones of visions, but also to the width of the old media stripe 310. In this way, new media stripe 300 is precisely overlaid onto old media stripe 310.

FIG. 5 is an aerial view of a media stripe and the cones of vision cast by the sensors and/or cameras. Sensors and/or cameras 130 and 140 are mounted in applicator head housing 100 such that the respective cones of vision 135 and 145 are aligned with or tangential to the edge 305 of old media stripe 310. The cones of visions are fixedly positioned such that the distances A and B from an edge 138 and 148 of the cones of vision to center line 150 of old media stripe 310 are equidistant. Thus, the width of old media stripe 310 is substantially equal to the total distances of A and B; and, in one embodiment, is also equal to the width of new media stripe 300 that is to be overlaid onto old media stripe 310. Accordingly, if the operator of the line striping apparatus misaligns the applicator head housing 100 and move the edges 138 and 148 of the cones of visions 135 and 145 of the sensors and/or camera off of edge 305 of old media stripe 310, the sensors and/or camera communicate/s this misalignment to controls 15, which repositions applicator head housing 100 via actuator 45 to realign cones of visions 135 and 145 so that their respective edges, 138 and 148, are again tangential to edge 305 of old media stripe 310.

Illustrated in FIG. 6 is an event where more than one media stripe has been previously applied to the surface and they do not exactly overlap. As shown in FIG. 6, old media stripe 310 is partially overlaid onto second old media stripe 320. In one embodiment, for example as shown in FIG. 2, first and second sensors and/or cameras 130 and 140, respectively, are adjustably mounted to applicator head 100 via first and second sensor and/or camera adjustment slots 130A and 140A. When, as shown in FIG. 6, two previously laid media stripe are not exactly overlaid on top of the other, the edge 138 of the first sensor and/or camera cone of vision 135 is positioned tangential or adjacent to the outermost edge of any previous media stripe (e.g., 320). Likewise, the edge 148 of the second sensor and/or camera cone of vision 145 is also positioned tangential or adjacent to the other outermost edge of any previous media stripe (e.g., 310). In an embodiment, media discharge nozzle 110 is adjustable. It can be raised or lowered relative to the surface to be painted so that the spray pattern of the media is made narrow or wide. In another embodiment, the media spray nozzle itself is adjustable so that the spray pattern of the media is made narrow or wide. When new media stripe 300 is predetermined to be a fixed width and such a width would not completely overlay both old media stripes, new media stripe 300 is applied so that center of the new media spray width 150 is the point at which equidistantly bisects the distance between edges 138 and 148 of their respective cones of vision. In this embodiment, new media stripe will be applied approximately in the middle of any number of old media stripes. 

What is claimed:
 1. An apparatus for overlaying a media stripe onto a media stripe previously applied to a surface comprising: a mobile frame housing controls; an applicator head comprising a first sensor which casts a first cone of vision onto the surface, the first cone of vision positioned tangentially to a first edge of the media stripe previously applied to the surface, a second sensor which casts a second cone of vision onto the surface, the second cone of vision positioned tangentially to a second edge of the media stripe previously applied to the surface, and a media nozzle adapted to spray media overlaid on the media stripe previously applied to a surface, the media nozzle positioned at a distance from the first and second sensor; and an extendable arm having one end attached to the frame and the other end attached to the applicator head, wherein when the applicator head is moved along the media stripe previously applied to the surface and either the first or second cone of vision from the first or second sensor is no longer tangential to the first or second edge of the media stripe previously applied to the surface, the first and second sensors communicate with the controls which instruct the extendable arm to reposition the first and second sensors such that the their respectable cones of vision center are again tangential to the first or second edge of the media stripe previously applied to the surface.
 2. The apparatus of claim 1, wherein the media nozzle is positioned at a fixed distance from the first and second sensor.
 3. The apparatus of claim 1, wherein the mobile frame is mounted to a carriage selected from the group consisting of a walk-behind cart, a self-propelled cart, a vehicle, and a towed trailer.
 4. The apparatus of claim 1, wherein the mobile frame further comprises a user interface providing the user with information regarding the status of the apparatus.
 5. The apparatus of claim 1, wherein the extendable arm is a worm screw, piston, belt, shaft, or hydraulic cylinder.
 6. An apparatus for applying a media stripe onto a surface comprising: a mobile frame housing controls; an applicator head comprising a media nozzle adapted to spray media onto a surface; a extendable arm having one end attached to the frame and the other end attached to the applicator head, wherein the extension of the arm is controlled by the controls; at least one camera mounted to the apparatus, mobile frame or applicator head, and in communication with the controls; wherein when the applicator head is moved along the surface, the at least one camera identifies a location on the surface where media should be applied, the at least one camera communicates with the controls, which communicates with the arm to align the applicator head and media nozzle over the location on the surface where media is to be applied.
 7. A method of applying new media on a media stripe previously applied to a surface with an apparatus comprising a mobile frame housing controls, an applicator head comprising a first sensor which casts a first cone of vision onto the surface, the first cone of vision positioned tangentially to a first edge of the media stripe previously applied to the surface, a second sensor which casts a second cone of vision onto the surface, the second cone of vision positioned tangentially to a second edge of the media stripe previously applied to the surface, a media nozzle adapted to spray media overlaid on the media stripe previously applied to a surface, the media nozzle positioned at a distance from the first and second sensor and an extendable arm have one end attached to the frame and the another end attached to the applicator head, the steps of positioning the applicator head over the media stripe previously applied to a surface so that the first sensor having a cone of vision adjacent to a first edge of the media stripe and the second sensor having a cone of vision is adjacent to a second edge of the media stripe previously applied to the surface; moving the mobile frame while simultaneously applying new media, whereby the movement of the apparatus misaligns the applicator head such that the first or second cone of vision from the first or second sensor is no longer tangential to the first or second edge of the media stripe previously applied to the surface and the new media stripe is not overlaid with precision onto the media stripe previously applied to the surface; communicating the misalignment from the sensors to the controls; communicating from the controls to the extendable arm to reposition the applicator head so that the first and second sensors cones of vision are realigned in that they are again tangential to the first or second edge of the media stripe previously applied to the surface, wherein misalignment of the applicator head does not interrupt simultaneously application of the new media. 